In treating tissue loss of fingertips, it is crucial to maintain functional length and to restore adequate nail complex. Microsurgical anastomosis can achieve this if it is feasible. When microsurgery reconstruction is not feasible, reconstruction of the fingertip with composite grafting and the abdominal pocket principle may have a satisfactory functional and aesthetic result. The operative technique is easier despite of the necessity of secondary flap division and skin graft surgery. Thus this method may be a good alternative in treating fingertip injury in selected cases those are not suitable for microsurgical anastomosis.

Keywords: fingertip, composite graft

Introduction

Fingertip amputation is a very common injury of the hand, and it can be seen either at emergency room or office practice. Even the functional loss seems to be minimal quite so often it harms the patient a lot because of functional and aesthetic reason. When the patient brought in the amputated part with him we ought to consider revascularization though it is usually a difficult job. Though the indicaton of microsurgical revascularization has been discussed controversially are still present. In case of situation which is infeasible for microsurgical revascularization , the method using the pocket principle is proposed. We experienced 6 cases of fingertip injuries reconstructed with composite graft and additional pocket principle and obtained a good results without remarkable donor site morbidity.

Materials and operation methods

From June 1999 to May 2000, we had six cases of complete fingertip amputation accepted for treatment with the pocket

principle. The six cases included5 males and 1 female with the average age of26 . All of the grafts survived ,except for one case(case 4), which sustained wound infection and finally failed. The detail data concerning these cases is presented in Table I.

Preoperative evaluation was important in weeding out the cases permitted ofbeing undergoing microsurgical anastomosis. The operation was carried out under regional block or general anesthesia as required. Using a rubber tourniquet at the base of digit, the injured tissue was irrigated and debrided. The amputated part was deepithelializated with a No. 15 blade and the nail matrix was preserved unless the nail bed itself had sustained injury. We repaired the injured nail bed with 6-0 absorbable suture material, and placed the original nail over the injured nail bed. The deepithelializated amputated part was sutured to the proximal stump after rigid fixation with Kirschner wires. The pocket was designed at the abdominal wall and comfortable enough to sustain immobilization of up to three weeks. The incision of about 2cm over the appropriate ipsilateral lower abdomen was made with the depth dependent on the length of amputated part. In cases where the patient owned heavy subcutaneous fat, suture the margin of the abdominal pocket to epithelium of the stump, instead of burying the furfur of the stump epithelium in the pocket for 3 weeks. Although the circulation of the deep fascia was better than the subcutaneous fat, we suspect the furfur of epidermis was the cause of the infection.

We prefer the local anesthesia to avoid the detachment of the fingertip fixation while the patient is awaken from general anesthesia. After three weeks , we carefully delivered the finger from the pocket. The shortage ofskin on the fingertip was covered with a skin graft from the thigh, abdomen or instep areas of foot . The abdominal wound was closed in layer. The Kirschner wires were removedafter a month.

Case examples

Case 1

The 17-year-old male sustained right middle finger by press machine injury and complete amputation at the total nail level (see fig. 1). The amputated part of finger included the total nail matrix, the bone of the distal phalanx and the pulp soft tissue. No sizable vessels for anastomosis were available after the initial debridement. For both functional and cosmetic reasons, the nail on the reattached finger was preserved. The reattached finger was inserted into a pocket made at the ipsilateral lower abdomen. Three weeks later (see fig. 2), the finger was removed from the pocket and covered with a skin graft, harvested from the instep area of foot. After one month , the nail of the finger showed good results, but the pulp seemed to be mildly atrophic. (see fig. 3)

Case 2.

The 30-year-old male sustained a crushing injury when his right hand was caught in a machine. At the time of injury, he lost his distal part of the right middle finger. It made the microsurgical anastomosis difficult (see fig. 4.) The severed nail bed was repaired and the reattached finger was inserted into a pocket in the ipsilateral lower abdomen using the previously described method. Three weeks later, the finger was removed from the pocket and covered with a split thickness skin graft harvested from instep area of foot. In this case, we preserved more adipofascial tissue for the bed of the skin graft under the impression of future atrophy.(fig 5.) After6 months , the results were satisfactory (see fig. 6.7).

Discussion

Of all body parts, the primary organ for putting human thoughts into action is the hand, and the importance of the fingertip cannot be overemphasized, in this respect, especially in carrying maneuvers that require delicacy and skill. The fingertips, vital to the functions of pinching and grasping, depend upon sufficient preservation of digital length and intact sensory functions to operate. Various techniques have been used in reconstruction of the fingertip defects accompanying nail injuries when microsurgical anastomosis is hard to perform.2. Delayed secondary healing, stump revision, skin graft, local flap, composite graft, free flap, as well as toe to finger transplantation, have all been proposed as remedies to this problem .3. Among these, composite graft of the amputated digit tip is the only possible mean of achieving a full-length digit with a normal nail complex if toe transplantation is excluded for the donor site morbidity.4, 5.

In 1989, Rose and Norris demonstrated that the cap technique, of non-microsurgical reattachment, was a simple and reliable method for the functional preservation of pulp tissue, as well as the normal esthetic appearance of the nail complex.6In 1993, Hirase reported a simple method, using ice-water and aluminum foil, for enhancing composite graft survival. Cooling the entire recipient site retards cellular degeneration in the graft until neovascularisation occurs.7The study conducted by Dr. Kuo and Hsiao, based on the analysis of thirty cases between 1991 and 1997, identified the following three significant risk factors contributing to poor graft survival: a history of smoking, a graft length longer than 1.2 cm, and a crush injury.8 In addition to these studies, Moiemen , in 1997, investigated the results ofthe composite graft replacements conducted on 50 children over a period of 3 years and 6 months. The report states that a total success rate of 61% if the fingertips were replaced within 5 hours.9

Despite of these encouraging results, even when all of the numerous methods for aiding survival rate are employed, the successful rate of the composite graft remains persistently fair. Obviously, after reviewing the lecture, the results of composite graft on adults is not good 10, 11. Brent reported the initial clinical experience in replantation of fingertip amputation without vascular anastomosis, using subcutaneous pocketing of deepithelialized composite grafts in 1979.12.Recently, Paik-Kwon Lee proposed reliable results from composite graft, using the pocket principle, in adults, and refined the detailed surgical experience in 1999.13

Six patients were treated in our hospital from July 1999 to April 2000 in accordance with the pocket principle. The six cases of fingertip reconstruction with a combination of composite graft and abdominal pocket principle were examined retrospectively. It was determined that favoring the salvage of all of the nail brought better results. The deepithelialized surface of pulp contacted to the fascia of external oblique muscle aponeurosis was sufficient for enhancing the circulation. There was one case of failure in our six patients. The failure was attributed to the severity of the compression injury and dirt in the wound14.

Based on our limited experience, we formulated the following opinions:

1.This solution was only used when microsurgery was found to be unsuitable.

2.This solution was suitable for adults, and not for non-cooperative children.

3.The amputated part that included total nail matrix obtain the best cosmetic result.

4.The thinner the patients are the more external circulation from deepithelized pulp because the amputee can be inserted into the aponeurosis of the external oblique muscle instead of the subcutaneous fat.

5.Affixing the margin of the abdominal pocket to the stump epithelium instead of burying the furfur of the stump epithelium in the pocket is more favorable.

6.Local anesthesia was enough for the operation.

7.Because of the heavy keratin layer, skin from the instep area of foot is a more suitable donor site for the skin graft than the inguinal area.

8.If preserved, putting more adipofascial tissue over the amputee, before skin grafting is done, can compensate for future tissue atrophy.

Table 1.Case analysis

Age

Sex

Nail

Bone

Injury

Length

Finger

STSG Donor

Package

Depth

Remove Nail

Case 1.

17

Male

Total

Distal phalanx

Crush

12mm

RD3

Instep

Ext obl. muscle

–

Case 2.

22

Female

1/2

Distal phalanx

Knife

Cut

12mm

LD5

Abdominal skin

Subcutaneous fat

+

Case 3.

30

Male

1/3

Distal phalanx

Knife Cut

10mm

RD3

Instep

Subcutaneous fat

–

Case 4.

18

Male

Total

Distal phalanx total

Avulsion

20mm

12mm

LD3,4

None

Ext obl. muscle

–

Case 5.

39

Male

1/2

Distal phalanx

Crush

12mm

LD2

Abdomen skin

Muscle

+

Case 6.

31

Male

Total

Distal phalanx

Cut

10mm

LD3

Instep

Subcutaneous fat

–

Fig 1.The amputee included the total nail matrix , bone of distal phalanx and soft tissue of pulp.

Fig 2.After division from abdominal pocket, the nail matrix was intact and the deepithelizated area was well circulation.

Fig 3.One month later, the finger became original length and health nail.